The present invention relates to a stacked film, and more particularly, to an insulating film for semiconductor having superior adhesion to a coating film formed by a CVD (Chemical Vapor Deposition) process in, for example, semiconductor devices.
Hitherto, silica (SiO2) films formed by a vacuum process such as a CVD process have been widely used as dielectric films in, for example, semiconductor devices. In recent years, insulating films of a coating type, comprising a hydrolyzate of a tetraalkoxysilane as a major component, which are called as SOG (Spin on Glass) films, have also been used for the purpose of forming more uniform dielectric films. In addition, as the degree of integration of, for example, semiconductor devices becomes large, dielectric films having a low dielectric constant comprising, as a major component, a polyorganosiloxane called as xe2x80x9corganic SOGxe2x80x9d, have been developed.
Especially, for example, as the semiconductor devices become larger in degree of integration or more multiple in lamination, dielectric film materials having a lower dielectric constant, preferably a dielectric constant of 2.5 or less, and having superior adhesion to a substrate, have been being demanded.
As materials having a low dielectric constant, compositions comprising a mixture of fine particles obtained by condensation of an alkoxysilane in the presence of ammonia and a basic partial hydrolyzate of an alkoxysilane (see JP-A-5-263045 and JP-A-5-315319) and coating solutions obtained by condensation of a basic partial hydrolyzate of a polyalkoxysilane in the presence of ammonia (see JP-A-11-340219 and JP-A-11-340220) have been proposed. However, these materials involved problems such that when used alone, the adhesion to a substrate is inferior and that the dielectric constant exceeds 2.5.
The present invention relates to a stacked film for overcoming the above-described problems. More particularly, an object of the present invention is to provide an insulating film for semiconductor having superior adhesion to a coating film formed by a CVD process as a dielectric film in, for example, semiconductor devices.
The present invention provides a stacked film comprising (A) a coating film having a carbon content of 60% by weight or more in a composition (this coating film will be sometimes referred to as xe2x80x9cfilm (A)xe2x80x9d) and (B) a film prepared by heating a hydrolytic condensate obtained by hydrolysis and condensation of at least one compound selected from the group consisting of compounds represented by the following general formulae (51) to (54) (this coating film will be sometimes referred to as xe2x80x9cfilm (B)xe2x80x9d):
HSi(OR51)3xe2x80x83xe2x80x83(51)
wherein R51 represents a monovalent organic group,
Raxe2x80x2Si(OR52)4-axe2x80x2xe2x80x83xe2x80x83(52)
wherein R represents a fluorine atom or a monovalent organic group; R52 represents a monovalent organic group; and axe2x80x2 represents an integer of from 1 to 2,
Si(OR53)4xe2x80x83xe2x80x83(53)
wherein R53 represents a monovalent organic group, and
R54bxe2x80x2(R55O)3-bxe2x80x2Sixe2x80x94(R58)dxe2x80x2xe2x80x94Si(OR56)3-cxe2x80x2R57cxe2x80x2xe2x80x83xe2x80x83(54)
wherein R54 to R57 may be the same or different and each represents a monovalent organic group; bxe2x80x2 and cxe2x80x2 may be the same or different and each represents a number of from 0 to 2; R58 represents an oxygen atom, a phenylene group, or a group represented by xe2x80x94(CH2)nxe2x80x2xe2x80x94, wherein nxe2x80x2 represents an integer of from 1 to 6; and dxe2x80x2 represents 0 or 1.
The present invention further provides an insulating film comprising the above-described stacked film.
The present invention further provides a substrate for semiconductor using the above-described insulating film.